Remove unused boost from CMakeLists.txt

Remove unused boost from CMakeLists.txt

This merge request affects 2 packages:

• PhysicsAnalysis/AnalysisCommon/ParticleEvent
• Reconstruction/eflowEvent

Affected files list will not be printed in this case

Adding @goetz ,@mhodgkin as watchers

added 23.0 Analysis JetEtmiss Reconstruction review-pending-level-1 labels

CI Result SUCCESS (hash 13351846)

	Athena	AthGeneration
externals
cmake
make
tests

Full details available on this CI monitor view. Check the JIRA CI status board for known problems
Athena: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 73884]

CI clean, changes look good from an L1 point of view. Approving - L1

removed review-pending-level-1 label

added review-approved label

added review-approved-tier0 label

Garbage day! Approving!

added review-approved-point1 label

mentioned in commit 263f04a5

merged

mentioned in merge request !64153 (merged)